Traffic signs have conventionally been manufactured of metal in such a way that the actual sign plate has been stamped from sheet metal onto which the required sign has been painted. In general, the mounting post of the traffic sign has been a metal tube or a metal profile bar. Traffic signs have been erected by the roadside or the side of the street either by sinking them into the ground or by employing various concrete base members or equivalent. In conventional traffic signs, the sign portion has been attached to the mounting post either integrally or by using lobes of different types, which has made it possible to replace a sign on a mounting post.
One disadvantage of conventional metal traffic signs has been their rigid construction, with the result that, in vehicle collisions with such signs, the damages have often been great. In traffic accidents, conventional traffic signs may cause damage not only to the vehicle but also to the driver and passengers. In accordance with studies on accidents that have been conducted in Finland, annually 20 persons die in crashes in which the damage has at least partially been caused by a traffic sign upon collision of a vehicle with the sign. For reasons of economy, metal traffic signs are normally made of a material susceptible to corrosion. When the paint layer covering the sign is damaged, corrosion can easily start spreading and may damage the entire sign. Salt used on roads has also accelerated corrosion of traffic signs and shortened the service life of conventional traffic signs, which is calculated to be about 5 to 10 years with metal signs. Moreover, from a ecological point of view, conventional metal traffic signs have not been recyclable.